This invention relates to an armature operation-release testing apparatus for testing the armature operating and releasing characteristics of an electromagnetic relay having an armature.
Principal operating characteristics of electromagnetic relays employing an armature adapted to be moved toward and away from a core include the operating characteristic and the releasing characteristic. The operating characteristic refers to the capability of attracting the armature toward the core in response to the application of a predetermined operating current to the electromagnetic coil, while the releasing characteristic refers to the capability of releasing the armature from the position attracted to the core to restore it to the original position when the operating current applied to the electromagnetic coil is switched over to a predetermined releasing current.
Electromagnetic relays of general type employing an armature for the make-break of contacts, for example, wire spring relays are generally so constructed that the armature and the movable contact are urged in the same direction, and the armature is mechanically connected to the movable contact through a card to actuate the same. In such relays, therefore, it is merely necessary to check the make-break of the contacts for testing the armature operating and releasing characteristics of the relays.
There are however some electromagnetic relays of special types in which an armature is urged in a direction normal to the direction of movement of a movable contact and is not mechanically connected to the movable contact to actuate the same. In such special electromagnetic relays, visual check of the movement of the armature is generally resorted to in the test for the armature operating and releasing characteristics due to the fact that the make-break of the contacts is not directly caused by the armature. However, such visual check of the movement of the armature in the relay is defective in that the complete operating state of the armature cannot be exactly distinguished from the so-called quasi-operating state in which the armature is not fully attracted toward the core. Further, the test resorting to this visual check is extremely inefficient.